1. Field of the Invention
The present disclosure generally relates to devices for and methods of protecting an actuator against overload conditions; and more particularly, to a device for and method of overload protection that utilize superelastic (also known as “pseudoelastic”) shape memory alloy based overload protection systems to accomplish the same.
2. Discussion of Prior Art
Active material actuators, such as shape memory alloy wires, are generally protected from mechanical overload by the use of mechanical springs or electrical control schemes to avoid damage to the actuators when the output load exceeds a recommended limit. Both of these measures, however, present various concerns in the art. For example, linear mechanical springs needed for overload protection tend to be bulky because of the conflicting requirements of high force threshold for the overload function necessary to enable normal operation, and low stiffness to restrict the maximum stress experienced by the actuator when the overload protection system is activated. The electrical/control schemes are more versatile, but they increase system cost.